Apparatus, system, and method for water contaminant testing

ABSTRACT

A system for detecting and quantifying an analyte in a liquid includes a vial including one or more pre-dosed reagents disposed in the vial. The vial is configured to hold a volume of a liquid including an analyte. The one or more pre-dosed reagents are dissolvable in the volume of the liquid to form a sample liquid solution comprising chromophores or fluorophores. The analyte and the one or more pre-dosed reagents react to yield the chromophores or fluorophores. The system further includes a detection device including a chamber configured to retain the vial, the detection device configured to quantify the analyte in the sample liquid solution.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/200,484, filed on Aug. 3, 2015 (docket no. 3538.2.1p), which isincorporated by reference herein in its entirety.

BACKGROUND

The detection of analytes in a liquid (e.g., contaminants in wastewater) has numerous useful applications. For example, contaminantmonitoring in manufacturing is important when water quality has a directimpact on materials manufactured and when water discharges are monitoredfor permit compliance. In agriculture, water that was previouslydirected to disposal by injection could be easily monitored forsuitability for crop irrigation. With the ability to quickly detect andmonitor major macro and micro minerals of dietary importance,Concentrated Animal Feeding Operations (“CAFO”) programs could beclosely monitored to ensure optimum production with minimal waste. Waterand waste water management is also important for industries andregulatory bodies involved in energy production and extraction.

Additionally, the revolution in hydraulic fracturing and horizontaldrilling methods has made formerly inaccessible oil and gas commerciallyprofitable. These methods depend on the use and management of largequantities of water. The ability to quickly and accurately determinewater quality is crucial to modern drilling, fracturing, and oilfieldprocessing of waste streams. Specifically, constituents in water need tobe determined for the following reasons:

1. Baseline water quality within the natural aquifers surrounding thepotential drilling area need to be determined before any drillingactivity takes place and monitored throughout the drilling andproduction process to ensure no cross contamination of water resourceshas occurred.

2. Metals (and other inorganic ions) and organic constituents must becompatible with drilling mud chemistries to optimize drilling schedules,reduce maintenance or equipment costs and meet environmental standardswhile drilling through aquifers.

3. Salt, metal ions, anions (especially borates) and organics must bemonitored to optimize gel chemistries for fracturing operations. (Badfracturing stages caused by unmanaged water quality can cost millions ofdollars over the life of a well.)

4. Depending on the geological formation, one recovers between 3 to 11barrels of water for each barrel of oil—this wastewater must be properlycollected, stored and disposed of or optimally reused. The accuratedetermination of normally encountered metals, anions, microbes andorganic constituents (usually coming up from the geological formation)is critical for mixing waste streams, reducing maintenance due toscaling and preventing corrosion of oilfield production and wastestorage and transportation assets.

5. Monitoring water constituents is critical for EOR (enhanced oilfieldrecovery) to maximize hydrocarbon recovery and to prevent damage to theformation (especially when produced and flowback waste waters areutilized).

Critical water monitoring is usually accomplished through a mixture ofcertified laboratory testing (for initial oilfield chemical developmentand environmental certifications) and on-site testing for operations andwaste water management. On-site chemical testing in the oilfield usuallyrelies on kits and instruments that were originally developed formunicipal and well water applications and suffer from the followingissues:

1. Most kits suffer from a limited dynamic range requiring timeconsuming dilutions and the resulting reduction in precision.

2. Many kits are titrimetric and require varying degrees of training andexperience to produce reliable results. (Even after one develops theskills to conduct the assay the tests suffer from accuracy issues due tovariability caused by the drop counting methods employed.)

3. During the time required for accurate off-site testing crosscontamination may substantially impact the fresh water sources.

4. Chemical testing kits also consume a considerable amount oftime—dilutions, conducting the tests and clean up between assays oftenconsumes critical time (especially during fracturing operations whenanalysis speed can prevent failed fracturing stages).

5. Methods that were developed for drinking water aquifers can sufferfrom interferences that are present in oilfield waters (resulting inlost revenue and problems from poor fracturing stages and plugging offormations and oilfield assets due to inaccurate or absent water testingresults). Methods that were developed for monitoring pH suffer fromissues that make them inaccurate when conductivities are extremely lowor moderately high.

6. Chemical testing kits that use instruments require specializedtraining and time-consuming reagent handling and calibration steps forproper function.

Rapid, sensitive and on-site water monitoring is also critical forensuring that waste water discharge meets contractual or environmentallimits for agricultural, municipal and industrial runoff requirements aswell as a critical step in waste water management.

SUMMARY

The subject matter of the present application has been developed inresponse to the present state of the art, and in particular, in responseto the shortcomings of testing liquids to quantify an analyte, that havenot yet been fully solved by currently available techniques.

According to one embodiment, a system for detecting and quantifying ananalyte in a liquid includes a vial including one or more pre-dosedreagents disposed in the vial. The vial is configured to hold a volumeof a liquid including an analyte. The one or more pre-dosed reagents aredissolvable in the volume of the liquid to form a sample liquid solutioncomprising chromophores or fluorophores. The analyte and the one or morepre-dosed reagents react to yield the chromophores or fluorophores. Thesystem further includes a detection device including a chamberconfigured to retain the vial, the detection device configured toquantify the analyte in the sample liquid solution.

According to one embodiment, the pre-dosed reagents include freeze-driedsolid reagents. In certain implementations, quantifying the analyteincludes quantifying the chromophores or fluorophores in the sampleliquid solution.

According to one embodiment, the detection device includes a pluralityof light sources, each light source configured to emanate light towardsthe sample liquid solution in the vial.

In some implementations, the detection device includes a firstphotosensitive detector positioned in the chamber opposite from at leastone of the plurality of light sources. According to one embodiment, thefirst photosensitive detector detects transmission of light through thesample liquid solution.

According to some implementations, the detection device includes asecond photosensitive detector positioned at an angle offset from directlight from plurality of light sources. According to one embodiment, thesecond photosensitive detector detects fluorescence of light from thesample liquid solution.

In some implementations, the plurality of light sources are eachmodulated at a fixed frequency.

According to one embodiment, the first photosensitive detector includesa photosensor configured to convert a light signal from the plurality oflight sources to a voltage signal, an amplifier configured to amplifythe voltage signal, and a demodulator configured to convert the voltagesignal to a direct current signal.

According to some implementations, the detection device further includesa control system including an analog to digital converter to measure thedirect current signal.

In some implementations, the detection device is configured to detectlight signals that pass through the sample liquid solution and convertthe detected light signals into digital signals to quantify thechromophores or fluorophores in the sample liquid solution.

According to one embodiment, a detection device for detecting andquantifying an analyte in a liquid includes a chamber configured toreceive and retain a vial including one or more pre-dosed reagentsdisposed within the vial. The vial is configured to receive and hold avolume of a liquid including an analyte and the one or more pre-dosedreagents are dissolvable in the volume of the liquid to form a sampleliquid solution including chromophores or fluorophores. The analyte andthe one or more pre-dosed reagents react to yield the chromophores orfluorophores. The device includes a plurality of light sources, eachlight source configured to emanate light towards the sample liquidsolution in the vial, a first photosensitive detector positioned in thechamber opposite from at least one of the plurality of light sources,and second photosensitive detector positioned at an angle offset fromdirect light from plurality of light sources.

In some implementations, the first photosensitive detector includes aphotosensor configured to convert a light signal from the plurality oflight sources to a voltage signal, an amplifier configured to amplifythe voltage signal, and a demodulator configured to convert the voltagesignal to a direct current signal.

According to one embodiment, a method for detecting and quantifying ananalyte in a liquid includes forming a sample liquid solution byinserting a volume of a liquid including an analyte into a vial with oneor more pre-dosed reagents dissolvable in the volume of the liquid toform a sample liquid solution including chromophores or fluorophores.The analyte and the one or more pre-dosed reagents react to yield thechromophores or fluorophores. The method includes quantifying theanalyte in the sample liquid solution by quantifying the chromophores orfluorophores in the sample liquid solution.

In some implementations, quantifying the chromophores or fluorophores inthe sample liquid solution includes detecting light transmission throughthe sample liquid solution using a first photosensitive detectorpositioned opposite a plurality of light sources and detecting lightfluorescence from the sample liquid solution using a secondphotosensitive detector positioned offset from direct light emanationfrom the plurality of light sources.

According to one embodiment, the method includes modulating the lightsources at a fixed frequency.

According to some embodiments, the method includes converting thedetected light transmission to an electrical signal. In someimplementations, converting the detected light transmission to anelectrical signal includes converting the detected light transmission toa voltage signal, amplifying the voltage signal, and converting theamplified voltage signal to a direct current signal.

According to some embodiments, quantifying the analyte in the sampleliquid solution includes detecting absorbance in the sample liquidsolution.

The described features, structures, advantages, and/or characteristicsof the subject matter of the present disclosure may be combined in anysuitable manner in one or more embodiments and/or implementations. Inthe following description, numerous specific details are provided toimpart a thorough understanding of embodiments of the subject matter ofthe present disclosure. One skilled in the relevant art will recognizethat the subject matter of the present disclosure may be practicedwithout one or more of the specific features, details, components,materials, and/or methods of a particular embodiment or implementation.In other instances, additional features and advantages may be recognizedin certain embodiments and/or implementations that may not be present inall embodiments or implementations. Further, in some instances,well-known structures, materials, or operations are not shown ordescribed in detail to avoid obscuring aspects of the subject matter ofthe present disclosure. The features and advantages of the subjectmatter of the present disclosure will become more fully apparent fromthe following description and appended claims, or may be learned by thepractice of the subject matter as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the subject matter of the presentdisclosure will be readily understood, a more particular description ofthe subject matter will be rendered by reference to specific embodimentsthat are illustrated in the appended drawings. Understanding that thesedrawings depict only typical embodiments of the subject matter of thepresent disclosure and are not therefore to be considered to be limitingof its scope, the subject matter will be described and explained withadditional specificity and detail through the use of the accompanyingdrawings, in which:

FIG. 1 is a schematic flow chart diagram of a method for testing water,according to one embodiment;

FIG. 2A is a perspective view of a vial containing a volume of water tobe tested, according to one embodiment;

FIG. 2B is a cross-sectional view of the vial of FIG. 2A, according toone embodiment;

FIG. 2C is a perspective view of a spectrometer device, according to oneembodiment;

FIG. 3 is a schematic circuit diagram for operation of the spectrometerdevice, according to one embodiment;

FIG. 4 is a chart showing absorbance (770 nm wavelength) as a functionof solids percent in wastewater for various sizes of latex microspheres,according to one embodiment;

FIG. 5A is a chart showing absorbance as a function of wavelength forvarious concentrations of iron, according to one embodiment;

FIG. 5B is a chart showing absorbance as a function of ironconcentration for various wavelengths, according to one embodiment;

FIG. 6A is a chart showing absorbance as a function of wavelength forvarious amounts of sulfate, according to one embodiment;

FIG. 6B is a chart showing absorbance as a function of sulfateconcentration for various wavelengths, according to one embodiment;

FIG. 7A is a chart showing fluorescence intensity as a function ofwavelength for various amounts of chloride, according to one embodiment;

FIG. 7B is a chart showing a fluorescence ratio of pure water to waterwith chloride as a function of chloride concentration; and

FIG. 8 is a schematic diagram of an embodiment of a system for detectingand quantifying an analyte in a liquid.

DETAILED DESCRIPTION

The subject matter of the present disclosure has been developed inresponse to the present state of the art in water and other fluidtesting procedures. Accordingly, the subject matter of the presentdisclosure has been developed to provide an apparatus, system, andmethod for testing water and other liquids for contaminants thatovercomes many or all or some shortcomings in the prior art.

Reference throughout this specification to features, advantages, orsimilar language does not imply that all of the features and advantagesthat may be realized with the subject matter of the present disclosureshould be or are in any single embodiment of the subject matter. Rather,language referring to the features and advantages is understood to meanthat a specific feature, advantage, or characteristic described inconnection with an embodiment is included in at least one embodiment ofthe subject matter of the present disclosure. Thus, discussion of thefeatures and advantages, and similar language, throughout thisspecification may, but do not necessarily, refer to the same embodiment.

Furthermore, the described features, structures, advantages, and/orcharacteristics of the subject matter of the present disclosure may becombined in any suitable manner in one or more embodiments and/orimplementations. In the following description, numerous specific detailsare provided to impart a thorough understanding of embodiments of thesubject matter of the present disclosure. One skilled in the relevantart will recognize that the subject matter of the present disclosure maybe practiced without one or more of the specific features, details,components, materials, and/or methods of a particular embodiment orimplementation. In other instances, additional features and advantagesmay be recognized in certain embodiments and/or implementations that maynot be present in all embodiments or implementations. Further, in someinstances, well-known structures, materials, or operations are not shownor described in detail to avoid obscuring aspects of the subject matterof the present disclosure. The features and advantages of the subjectmatter of the present disclosure will become more fully apparent fromthe following description and appended claims, or may be learned by thepractice of the subject matter as set forth hereinafter.

Similarly, reference throughout this specification to “one embodiment,”“an embodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the subject matter of thepresent disclosure. Appearances of the phrases “in one embodiment,” “inan embodiment,” and similar language throughout this specification may,but do not necessarily, all refer to the same embodiment. Similarly, theuse of the term “implementation” means an implementation having aparticular feature, structure, or characteristic described in connectionwith one or more embodiments of the subject matter of the presentdisclosure, however, absent an express correlation to indicateotherwise, an implementation may be associated with one or moreembodiments.

Various embodiments of the present invention allow water samples to bequickly tested for analytes in very few steps, with little need fortraining and with no need for reactive or labile liquid reagents.Detection of the analytes is accomplished through chromogenic orfluorescence testing initiated by reconstitution of pre-dosed vialscontaining solid or freeze-dried reagents with the sample where thedetected analyte is quantified through use of absorption or fluorescencechromophores generated by reaction with the analyte and as quantified bya detection instrument capable of converting detected light signals intoelectronic signals. In some embodiments, an analyte reacts with reagentsprovided in a pre-dosed vial with said pre-dosed vial determining whichanalyte is to be detected and quantified. Another embodiment of theinvention uses the human eye verses a comparison chart to quantify thechromophore in the sample. Yet another embodiment of the presentinvention would utilize the photographic image of the test vial and useof a comparison to known color values to quantitate the chromophore (andthus the analyte) in the sample. Some embodiments utilize the benefitsof the dried, pre-dosed vials.

FIG. 1 shows a diagram 100 illustrating the steps and processesnecessary to practice an embodiment of the present invention. In step 1,a specific amount of a sample including an analyte is used toreconstitute a sample vial containing dried chemicals specific for thedetection and quantitation of the analyte in question. The sample vialis mixed to completely dissolve the dried reagent in step 2. In step 3,the reconstituted vial is placed in an optical chamber 824 (see e.g.,FIG. 8) of a detection device capable of determining an amount of lighttransmitted through, scattered, and emitted due to fluorescence. Foreach light source, the light is frequency modulated and passed into thesample vial. In some embodiments, detection of the transmitted lightintensity is accomplished using photodetectors directly in the path ofthe respective light source on the other side of the sample vial. Insome embodiments, detection of the scattered and fluorescent light isaccomplished using a photodetector at a right angle to the sample vial.Amplification followed by analog-to-digital conversion and demodulationconverts the signal detected into a digital signal, which is used toquantitate the analyte in question. The reconstitution, mixing andplacement of the mixed sample is required only once per sample whereasthe frequency modulation, amplification and demodulation of eachtransmitted light and scattered light signals is required for each lightsource used.

FIGS. 2A and 2B further show the mechanical relationship of a lightsource directed into the sample (1), the transmitted light (2) and thefluoresced and scattered light (3) relative to the sample vial (bothside and top views). Some embodiments teach the use of multiple lightsources with various wavelengths which should be aimed at aphotodetector opposite the optical chamber for the detection oftransmitted light (see e.g., photodetector 220) and an additionalphotodetector at a right angle to the transmission photodetector for thedetection of scattered and fluoresced light signals (see e.g.,photodetector 222). The embodiment Illustrated in FIG. 2C shows amechanical assembly allowing multiple laser light sources 202, 204, 206aimed at different angles so as to strike the active area of a singlephotodetector opposite the sources; the aperture 208 for the additionalphotodetector used to detect fluorescence and scattering can be seen. Inan embodiment of the invention, angling all light sources to a singledetector opposite allows detection of both transmission and fluorescenceand scattering with only two photodetectors as long as each light sourceis modulated separately.

FIG. 3 shows the circuit diagram of how frequency modulated light isconverted to an electrical signal by use of photosensitive detectorwhose signal is amplified then subsequently demodulated to produce a DCsignal that is measured by an analog to digital converter. In someembodiments, demodulation is accomplished using a balanced demodulatorconfigured as a lock in amplifier.

FIG. 4 shows the absorbance at 770 nm in water with varying amounts andsizes ( 0.202 μm, ⋄ 0.548 μm and Δ 1.053 μm) of latex microspheres.This shows that the amount of absorbance due to scattering can bepredicted for a wide variety of particle sizes normally observed inhydraulic fracturing flowback wastewater.

FIG. 5A is a chart showing absorbance as a function of wavelength forvarious concentrations of iron. FIG. 5B is a chart showing absorbance asa function of iron concentration for various wavelengths.

FIGS. 5A and 5B show the absorbance spectra (A) of the1,10-phenanthroline reaction with varying amounts of iron. (As theamount of iron present in the sample increases, so does the absorbanceform the generated chromophore present.) The effect of total iron in thesample on the calculated absorbances from the 460 nm () and 525 nm (⋄),and 770 nm (Δ) transmissions in an embodiment of the invention is shown.The calculated absorbance values at 460 and 525 nm are useful todetermine how much of the chromophore is present; the calculatedabsorbance value at 770 nm is insensitive to the chromophore but can beused to predict the contribution at 460 and 525 nm of the calculatedabsorbance from scattering in the sample.

FIG. 6A is a chart showing absorbance as a function of wavelength forvarious amounts of sulfate. FIG. 6B is a chart showing absorbance as afunction of sulfate concentration for various wavelengths.

FIGS. 6A and 6B show the absorbance spectra (A) of the barium reactionwith varying amounts of sulfate. (As the amount of sulfate present inthe sample increases, so does the absorbance due to scattering from thegenerated solids present.) The effect of sulfate in the sample on thecalculated absorbances from the 660 nm (⋄) and 525 nm (Δ) transmissionsin an embodiment of the invention is shown.

FIG. 7A is a chart showing fluorescence intensity as a function ofwavelength for various amounts of chloride. FIG. 7B is a chart showing afluorescence ratio of pure water to water with chloride as a function ofchloride concentration.

FIGS. 7A and 7B show the fluorescence spectra (A) of the bufferedquinine interaction with varying amounts of chloride. (As the amount ofchloride present in the sample increases, the fluorescence is quenched.)B shows the effect of chloride in the sample on the calculated ratio ofthe fluorescence from pure water (F0) to the sample (F) upon excitationwith ultraviolet light ().

Embodiments of the present invention describe a method, a system, and anapparatus. Referring to FIG. 8, the system and/or apparatus can beconstructed to practice embodiments of the method, for the detection andquantitation of an analyte 810 in a solution or liquid 808 by reactionwith a reagent 806 or collection of reagents 806 that will result in achange in color or fluorescence; this change in color or fluorescencecan be used to subsequently determine the concentration of the analyte810. This method may be practiced where all the reagents 806 necessaryto result in detection and quantitation are pre-dosed and dried in areaction vial 802 in a manner that will result in them being quicklydissolved when reconstituted with the sample (e.g., liquid 808).Successful production of the pre-dosed reaction vials 802 requires thatthe chromogenic chemistries are compatible with substances that arelikely to be present in the sample and may require bulking agents,whether buffering salts, soluble starches, other organic compounds thatwill not interfere with the reaction chemistries, unreactive inorganicsalts, or a mixture thereof. In some embodiments, if the reactionchemicals are not compatible with each other before reaction with theanalyte 810, it is necessary to freeze these incompatible reagentsseparately in the vial before freeze-drying or be kept physically apartin the same vial then freeze-dried separately.

The quantitation of the resulting chromophores or fluorophores isaccomplished using an apparatus capable of measuring the amount oftransmittance through and fluorescence from the reconstituted sample(e.g., a sample liquid solution) in the vial 802. An apparatus (e.g.,detection device 804) includes two or more light sources 822 (optimallypracticed using LASER diodes or light emitting diodes (LEDs) that aremechanically aimed at the active area of at least two photodetectors812); at least one of these photodetectors 812 should be oriented tomeasure transmission through the sample of the various light sources andat least one of the other photodetectors 812 be mechanically oriented atan angle large enough to measure fluorescence and scattering. (Theabsorbance due to the sample from each light source can be calculated bycomparison to sample vials reconstituted with a solution without theanalyte.)

In an embodiment of the invention the light sources 822 are modulated ata fixed frequency and power levels and the subsequent transmitted,scattered and fluoresced amount of light is converted to an electricalsignal by use of the photosensitive detectors 812 whose signals areamplified and demodulated to produce a direct current (DC) signal thatis measured by an analog to digital converter (ADC); demodulation of theDC signal is accomplished using a balanced demodulator configured as alock in amplifier. Ultimately, the concentration of the analyte in theoriginal solution is calculated from the contribution to the detectedand demodulated signals from the resulting chromophore or fluorophorefrom which the contribution of scattering has been subtracted. Furtherdetails of the disclosed embodiments are provided below.

The detection and quantitation of each analyte in a sample isaccomplished by the reaction of the analyte in the sample with driedreagents in the sample vial that will yield a chromophore, a fluorophoreor both, with the quantities of said chromophores or fluorophores beingdetermined by the quantity of the analyte in question. The quantitationof said chromophores or fluorophores is used to quantitate the amount ofanalyte present in the sample.

Quantifying the absorption or fluorescence chromophores generated byreaction with the analyte can be accomplished using a detectioninstrument capable of converting detected light signals into electronicsignals. Said detection instrument is capable of detecting bothabsorbance (via measurement of transmission and the subsequentconversion of this measurement to absorption by comparison to theexpected result of a pure water sample tested with the testing vials)and fluorescence. Such an instrument is constructed using mechanical andoptical components to deliver light to the sample vials in areproducible manner and electronics capable of detecting light that istransmitted, scattered or due to fluorescence from the sample. Thesefunctions are accomplished through the use of three subsystems: lightsources, detectors and a control system.

In an embodiment of the invention light is produced by solid state lightsources 822 such as light emitting diodes or diode lasers. To reduce theeffect of noise and ambient light, the light sources 822 are modulatedat a fixed frequency. To compensate for changes in light source efficacyover temperature, an optical feedback system can be used to monitor thelight source output and adjust the drive current as required. Light fromthe sources is directed through the sample to a photosensitive detector812 that measures transmission. A second detector 812, facing the sampleat an angle, measures scattering and fluorescence. The detector portionof the system consists of three stages: a photosensor 814, variable gainamplifier 816, and demodulator 818. The photosensor stage converts thelight to a voltage signal. This signal is then amplified in the variablegain stage. The gain of this stage is adjustable to extend the dynamicrange of the system and maximize the range of samples that can bemeasured by the system. After amplification, the signal is demodulatedto produce a DC signal, which is measured by the analog to digitalconverters in the control system. Demodulation of the signal isaccomplished using a balanced demodulator configured as a lock inamplifier. This design allows for a very narrow bandwidth. By narrowingthe bandwidth, the effect of thermal noise, which is proportional to thesquare root of the bandwidth, is significantly reduced. This also allowsfor greater rejection of interference from fixed frequency sources.

The use of modulated light sources also significantly reducesinterference from ambient light. The system electronics are controlledby an embedded microcontroller. The system can be run in two differentmodes: a ‘stand alone’ mode or in a ‘remote’ mode where the userinteracts with the device through a computing device connected by anelectronic interface. In ‘stand alone’ mode, the control system handlesuser input of measurement parameters, collection of transmission,scattering, and fluorescence measurements, analysis of the collecteddata, and display of the results to the user. In ‘remote’ mode, thissystem handles reception of commands from the connected computingdevice, collection of transmission, scattering, and fluorescencemeasurements, and transmission of the collected data back to theconnected computing device.

Though the present invention has been designed to reduce the number ofsteps and lab ware needed to accomplish chemical monitoring tasks itwill be appreciated by one skilled in the art that embodiments canadditionally be practiced in conjunction with an auto feed unit. Byautomating the placement, movement and positioning of pre-dosed testingvials it should be possible to remove all human steps during themonitoring process.

It will be appreciated by one skilled in the art that the use offrequency modulation in both the transmissive and fluorescence detectionof transmitted and fluoresced light eliminates the background signalassociated with the instrument. Using either methods from electroniccircuit design or the mathematical solution to the real portion ofFourier Transform of the raw detected signal (with the constant set tozero) from frequency-modulated light used for either transmission orfluorescence excitation allows the user to eliminate the portion of anydetected signal that arises from the electronics of the instrument. (Forfluorescence this requires the frequency modulation to be significantlyslower than the fluorescence lifetime of the excited state of thefluorescing species.) This leaves the detected signal being comprised ofa reduction in transmission resulting from the absorption of chemicalspecies in the sample resulting from generation of chromophores inchemical assay and from scattering by microscopic materials alreadypresent in the sample. The transmitted light can be converted intoabsorbance values using the equation Absorbance=log(To/T) where To isthe transmission observed for pure water when used in the assay and T isthe transmission obtained when using the sample. Conversion of thetransmission to absorbance allows one to calculate the contribution ofthe signal from scattered light provided one knows or can estimate thesize of the scattering particles, especially if absorbance values in thesample are collected at lower energy (higher wavelength) values.Accounting for the portions of the signal from the detection instrumentand from scattering allows one who practices the present invention touse pre-determined values from the chromophore or fluorophore in theassay thus eliminating the need for a sample blank for each sample,eliminating the cost and additional sample manipulations associatedtherewith.

In an embodiment of the present invention it is useful to employ thedetection and calculation of numerous wavelengths of light used todetect chromophores resulting from rapid chemical assays for any givenanalyte, said wavelengths ranging from the ultraviolet to the nearinfrared. The detection of these several wavelengths has at least threemain benefits: (1) it allows for the instrument to be used with a widervariety of chemical assays, each detectable through the absorption ofdifferent wavelengths of light energy, (2) the detection of nearinfrared light allows the user to compensate for any scattering fromminerals or microbes present from the sample, and (3) the detection ofmultiple wavelengths allows for the use of multivariate analysis tobetter determine the accurate concentration of the analyte from theassay used with the sample. Additionally, various algorithms (includingneural networks and the like) can be employed to increase the accuracyof both detection and quantitation of the analytes in the chemicalassays by using these multiple wavelengths.

It will also be appreciated by one skilled in the art that an embodimentof the present invention may use freeze-dried reagents for the chemicalassays. Such an embodiment allows one to eschew the use of liquidreagents, which are susceptible to decomposition at elevatedtemperatures or freeze at depressed temperatures normally encountered inthe field. The use of freeze-dried reagents allows the assays to bestored for extended periods of time and under conditions that would bedetrimental to assays that utilize dissolved reagents.

The use of freeze-dried or solid reagents also allows the presence ofall reagents necessary to conduct the assay to be placed in a singlevial; this is especially useful if the various reagents react with eachother either slowly over time or with deleterious effect without thepresence of the analyte. By mixing and freeze-drying the reagentsquickly or at depressed temperatures, it is sometimes possible tominimize the effect these side-reactions have on the performance of theassay. On many occasions it is preferable to freeze incompatiblereagents separately to prevent their reaction either beforefreeze-drying or to freeze-dry them in different areas of the vial,preventing them from making contact in the liquid state and thusreacting. This practice of the present invention allows all necessaryreagents to be present when the assay is reconstituted in the liquidstate by the sample; this allows the number of steps required tocomplete the assay to be reduced to simply reconstitution of thereagents with the sample, mixing and determining the concentration usingthe absorbance or fluorescence detection instrument. It willadditionally be appreciated by one skilled in the art that the practiceof embodiments of the present invention greatly reduce the number ofsteps required to perform a titrimetric assay, where known quantities ofa standardized solution containing a necessary reagent is added until anendpoint is reached, whereby the concentration of the analyte iscalculated from the amount of titrant added but conducting the assayrequires the additional steps associated with said titration.

In an embodiment of the present invention the chemical reagents used inthe chromogenic or fluorescence assay is chosen to be compatible withthe kind of water sample. For example, flowback and produced formationwaters recovered in hydraulic fracturing operations from many geologicalformations are likely to be high in alkaline earth metals, which arelikely to form scale precipitates if exposed to high pH conditions ofcertain assays. Thus it is preferable to account for deleteriousreactions that might occur between chemical components in the assay andchemical species that are likely to form precipitates or containnaturally occurring chemical species that absorb or fluoresce in aregion that will interfere with the chromophores or fluorophoresgenerated in the assay. Thus, in an embodiment of the invention, thechoice of the chemical species used in the assay is chosen to becompatible with what is likely to be present in the water sample.

For lower volume samples the amount of reagents required to conduct theassay is usually quite low. When small amounts of organic and inorganicmaterials are freeze-dried they will often become closely associatedwith the vial surface or crystalize and exhibit a reluctance to quicklydissolve, thus increasing the time and effort required to conduct theassay. It is therefore preferable that other materials be added to theassay mix so that when the reagents are co-dried with said materialsthey will both quickly dissolve and keep from either becoming tootightly associated with the vial or crystalizing. In traditionalchromogenic assays a small amount of sample is added to a larger volumeof solution where the pH and conductivity is carefully controlled sothat the quantity of analyte can be accurately calculated from theamount of chromophore.

In an embodiment of the present invention it is necessary to provideenough buffering agent to control the pH and conductivity of the sample;this buffering agent can often be used as the material co-dried with thereagents to ensure rapid reconstitution. It is important, however, tochoose buffering agents that will be compatible with the assay reagentsand the components present in the sample. Additionally, solublecellulose fibers or salts can be used for this purpose. Soluble, highmolecular mass cellulose fibers such as arabinogalactans that do notinterfere with an assay are useful for this purpose as they can be addedwithout depressing the freezing point of the mixture too much makingfreeze-drying difficult. Alternately, a salt such as potassium chloride(which does not alter the pH of the solution) can be used for thispurpose as well as increasing the ionic strength of the final testingsolution (when this is desirable). In an embodiment of the invention,the choice of bulking agent used to co-dry with the analysis chemicalsis based upon the needed buffering capacity relative to the sample andthe chemical compatibility of said bulking agent with the assay.

The detection of calcium in waters and wastewaters is useful forpurposes of determining the potential for scale, suitability forirrigation (sodicity) and determining what kind and concentration ofadditives will be required for oilfield use (amongst otherapplications). It will be appreciated by one skilled in the art thatthere are numerous colorimetric and fluorescence chemistries that can beused for the detection and quantification of calcium to be practicedwith the present invention, these methods chosen depending on thedesired calcium concentration detection range, pH and presence ofinterfering ions or other chemistries.

An example of these chemical methods is the use of chlorophosphonazo orarsenazo dyes, where any calcium present in the sample reacts with thedye and produces a chromophore wherein the concentration of the calciumcan be determined from the concentration of the chromophore generated.By control of the pH through provision of enough buffering chemicals toovercome the expected buffering capacity of the sample all alkalineearth metals are detected at neutral and higher pH values; magnesium(the second most prevalent alkaline earth metal) does not form complexeswith these chromophores at lower pH values. The relative concentrationsof barium, strontium and radium are so small relative to calcium innatural samples that their respective contributions to the calciumsignal are negligible. Fluorophores such as calcein andchlorotetracycline can be used to detect calcium with ultravioletexcitation at pH values of approximately 8 and 7, respectively. It willbe appreciated by one skilled in the art that the detection andquantitation of hardness (total alkaline earth metals measured asmilligrams per liter calcium carbonate) would be accomplished bypracticing the calcium detection with an appropriate chemistry at a pHwhere calcium, magnesium, barium, strontium and radium are all detected.

The detection of boron in waters and wastewaters is useful for purposesof determining the potential for interference in fracturing chemical gelformation (along with suitability for waters for other applications).There are numerous colorimetric and fluorescence chemistries that can beused for the detection and quantification of boron to be practiced withthe present invention, these methods chosen depending on the desiredboron concentration detection range, pH and presence of interfering ionsor other chemistries. An example of these chemical methods is the use ofazomethine-H, ammonium chloride and ascorbic acid, where any boronpresent in the sample reacts with the reagents producing a chromophorewherein the concentration of the boron can be determined from theconcentration of the chromophore generated. pH is controlled by additionof enough 2-(N-morpholino)ethanesulfonic acid (and its sodium salt) toovercome the expected buffering capacity of the sample. Fluorophoressuch as 2,3-DNHS can be used to detect boron with ultravioletexcitation.

The detection of pH in waters and wastewaters is useful for purposes ofdetermining the potential for interference in fracturing chemical gelformation along with suitability for waters for other industrial,discharge and agricultural applications. pH monitoring is especiallydifficult when the sample has extremely low conductivity or moderatelyhigh conductivity as traditional electrochemical monitoring is optimizedfor dilute solutions containing only inorganic salts. There arecolorimetric and fluorescence chemistries that can be used for thedetermination of pH that can be practiced with the present invention,these methods chosen depending on the desired pH determination range, pHand presence of interfering materials or other chemistries. An exampleof these chemical methods is the use of neutralized universal indicatorand salt (potassium chloride), where the pH is determined bymultivariate analysis of the relative amounts of colors present.Potassium chloride is added to overcome any expected changes in the pKasof the indicator salts as the effects of salinity on the pKa transitionsis less at higher salt concentration. Fluorescent indicators to pH, suchas eosin yellowish and eosin blueish, can be utilized at low pH values.

The quantitation of alkalinity in waters and wastewaters is useful forpurposes of determining the Langelier Saturation Index (useful indetermining the potential for scaling or corrosion) along withsuitability for waters for other industrial, discharge and agriculturalapplications. This is accomplished by addition a known amount of sampleto a known amount of weak acid that has been buffered to a pH of 4.2;the same colorimetric or fluorimetric chemistries that can be used forthe determination of pH can be used to determine the resulting pH andthus the amount of total alkalinity (hydroxide and bicarbonate) can becalculated from a calibration curve previously determined. In anembodiment of the present invention, citric acid is used because itbuffers over the most useful pH range for this assay, but the choice ofweak acid and the concentration used thereof should be chosen dependingon the desired total alkalinity determination range, pH and presence ofinterfering materials or other chemistries. An example of these chemicalmethods is the use of universal indicator and salt (potassium chloride),where the pH is determined by multivariate analysis of the relativeamounts of colors present. Different amounts of weak acid can be used toproduce assays that have larger or smaller ranges of total alkalinity.

Chloride determination in waters and wastewaters is useful for purposesof estimating total dissolved solids as the most prevalent salt inwastewaters is sodium chloride. There are numerous colorimetric andfluorescence chemistries that can be used for the detection andquantification of chloride to be practiced with the present invention,these methods chosen depending on the desired chloride concentrationdetection range, pH and presence of interfering ions or otherchemistries. An example of these chemical methods is the use of quininesulfate, where any chloride present in the sample quenches thefluorescence from the quinine, wherein the concentration of the chloride(and other rare halides) can be determined from the degree of quenchingcompared to a solution of pure water when excited with ultravioletlight. The pH is controlled by addition of enough sulfamic acid andsodium citrate to overcome the expected buffering capacity of thesample.

Copper determination in waters and wastewaters is useful for purposes ofquantifying this micronutrient for agricultural purposes and forverifying its presence for biocidal activity. There are numerouscolorimetric and fluorescence chemistries that can be used for thedetection and quantification of copper to be practiced with the presentinvention, these methods chosen depending on the desired copperconcentration detection range, pH and presence of interfering ions orother chemistries. An example of these chemical methods is the use ofcalcein, where any copper present in the sample quenches thefluorescence from the calcein, wherein the concentration of the coppercan be determined from the degree of quenching compared to a solution ofpure water when excited with ultraviolet light. The pH is controlled byaddition of enough citric acid and sodium citrate to overcome theexpected buffering capacity of the sample.

The detection of hexavalent chromium in waters and wastewaters is usefulfor purposes of determining the suitability for discharge oreffectiveness of treatment regimes. There are numerous colorimetric andfluorescence chemistries that can be used for the detection andquantification of hexavalent chromium to be practiced with the presentinvention, these methods chosen depending on the desired hexavalentchromium concentration detection range, pH and presence of interferingions or other chemistries. An example of these chemical methods is theuse of 1,5-diphenylcarbazide, where any hexavalent chromium present inthe sample reacts with the reagents producing a chromophore wherein theconcentration of said hexavalent chromium can be determined from theconcentration of the chromophore generated. pH is controlled by additionof enough buffered sulfamic acid to overcome the expected bufferingcapacity of the sample.

The detection of iron in waters and wastewaters is useful for purposesof determining the potential for interference in fracturing chemical gelformation, the tendency to form scale and for waters for otherindustrial and agricultural applications. There are numerouscolorimetric and fluorescence chemistries that can be used for thedetection and quantification of iron to be practiced with the presentinvention, these methods chosen depending on the desired ironconcentration detection range, pH and presence of interfering ions orother chemistries. An example of these chemical methods is the use of5-sulfosalicilic acid or 1,10-phenanthroline, where any iron present inthe sample reacts with the reagents producing a chromophore wherein theconcentration of the iron can be determined from the concentration ofthe chromophore generated. Speciation between divalent, trivalent ortotal iron is determined by pH, which can be controlled by addition ofenough citric acid (and its sodium salt) to overcome the expectedbuffering capacity of the sample.

The detection of sulfate in waters and wastewaters is useful forpurposes of determining the potential for barite and other alkalineearth metal scale formation along with suitability for waters fordischarge and agricultural applications. There are numerous colorimetricand fluorescence chemistries that can be used for the detection andquantification of sulfate to be practiced with the present invention,these methods chosen depending on the desired boron concentrationdetection range, pH and presence of interfering ions or otherchemistries. An example of these chemical methods is the use of acidicbarium hydroxide or barium violurate, where any sulfate present in thesample reacts with the reagents producing either a precipitate that willabsorb and scatter light or a chromophore wherein the concentration ofthe sulfate can be determined from the concentration of the precipitateor chromophore generated. pH is controlled by addition of enough maleicanhydride and sodium citrate to overcome the expected buffering capacityof the sample.

The detection of sulfide in waters and wastewaters is useful forpurposes of determining the potential for scale formation, corrosivetendencies and the suitability for waters for discharge and other uses.There are numerous colorimetric and fluorescence chemistries that can beused for the detection and quantification of sulfide to be practicedwith the present invention, these methods chosen depending on thedesired sulfide concentration detection range, pH and presence ofinterfering ions or other chemistries. An example of these chemicalmethods is the use of buffered 6,6′-Dinitro-3,3′-dithiodibenzoic acid,where any sulfide present in the sample reacts with the reagents achromophore wherein the concentration of the sulfide can be determinedfrom the concentration of the chromophore generated. Alternately, thesulfide can be reacted with N,N-Dimethyl-p-phenylenediamine in thepresence of iron chloride to produce a chromophore; buffering withsulfamic acid results in formation of methylene blue that can be used toquantitate the sulfide.

The detection of miscible volatile or semi-volatile organic compounds(VOCs) in waters and wastewaters is useful for purposes of determiningthe potential for interference in fracturing chemical gel formation aswell as suitability for waters for other applications or discharge.There are numerous colorimetric and fluorescence chemistries that can beused for the detection and quantification of VOCs to be practiced withthe present invention, these methods chosen depending on the desiredVOCs concentration detection range, pH and presence of interfering ionsor other chemistries. An example of these chemical methods is the use ofa buffered solvatochromatic dye like N,N-Dimethylindoaniline, where anyVOC (such as acetone, alcohols and the like) present in the sampleassociates with the reagents producing a chromophore wherein theconcentration of the VOC can be determined from the concentration of thechromophore generated. pH is controlled by addition of enough bufferingsalts to overcome the expected buffering capacity of the sample.

The detection of viable microorganisms in waters and wastewaters isuseful for purposes of determining the potential for microbial inducedcorrosion, waterflooding and other enhanced oilfield recovery operationsas well as suitability for waters for other applications or discharge.There are numerous colorimetric and fluorescence chemistries that can beused for the detection and estimation of microbial concentration to bepracticed with the present invention, these methods chosen depending onthe desired microbial content detection range, pH and presence ofinterfering biocides or other chemistries. An example of these chemicalmethods is the use of a buffered metabolic dye precursor such asresulin, where metabolic activity (and thus viable microorganismscapable of metabolizing the dye precursor) present in the sampleproduces a chromophore when excited with green light wherein theconcentration of the microbes can be determined from the concentrationof the chromophore generated if incubated at the correct temperature andfor the proper amount of time. pH is controlled by addition of enoughbuffering salts to overcome the expected buffering capacity of thesample and other necessary nutrients can be added to the reactionmixture. It will be appreciated by one skilled in the art that thedesired level of specificity in microbial species identification may beintroduced by selecting a chromogenic precursor that is metabolized onlyby the kingdom, genera, genus, species or subspecies of interest.

It will also be appreciated by one skilled in the art that theprinciples outlined in the present disclosure can be applied to fluidsother than water. For example, extract solutions of solid samples whichsolubilize analytes into the fluid phase can be employed or other fluidslike urine can be analyzed using the same methodology providedchromophores or fluorophores utilized to detect the analyte in questiondo not exhibit similar absorption or fluorescence to the sample. Organicliquids can also be analyzed using the same methodology: with organicsolutions it is necessary that the vial be compatible with the solution,the organic liquid be somewhat transmissive to light in the energyregions utilized by the chromophores, and that the chromophores orfluorophores utilized to detect the analyte in question do not exhibitsimilar absorption or fluorescence to the organic liquid.

In summary, the present disclosure relates to a system, apparatus, andmethod for the detection and quantitation of an analyte in a solution byreaction with a reagent or reagents that result in a change in colorand/or fluorescence. The concentration of the analyte can be related tothe amount of change in color or fluorescence.

Regarding the reagents and the pre-dosed vial:

All the reagents required to complete the reaction may be provided aspre-dosed, freeze-dried solids that will quickly dissolve upon additionof the liquid sample.

The freeze-dried reagents may contain enough buffering agents that willexceed the buffering capacity of the sample resulting in a defined pHrange for the reaction.

The freeze-dried reagents contain (if necessary) a bulking agent thatwill not interfere with the chemical assay to keep said reagents fromcrystalizing or becoming too associated with the walls of the vial inwhich the reaction is conducted.

The bulking agent may be an unreactive salt, buffering substances, acarbohydrate or other organic substance that doesn't interfere with thereaction, a soluble higher molecular weight starch if a freezing pointdepression is not desired, or a mixture of salts, buffering substances,soluble starches and other organic materials that do not interfere withthe analyte detection chemistries.

The reagents, if chemically incompatible with each other before reactingwith the analyte, can be frozen separately in the reaction vial beforefreeze-drying or kept physically apart and freeze-dried separately;

The freeze-dried reagents used in the chromogenic or fluorescence assayare chosen to be compatible with the kind of water sample;

Regarding the spectrometer device for detection and quantitation of thechromophores or fluorophores:

The light sources used for transmission and fluorescence excitationsources can be light emitting diodes, laser diodes, or some other typeof light source.

The light sources used for transmission excitation sources may includeat least one that emits light at a wavelength that is sensitive to thepresence of the chromophore.

The light sources used for fluorescence excitation sources may includeat least one that will excite the fluorophore used for detection.

The light sources used for transmission or fluorescence excitationsources may include at least one that emits light at a wavelength usefulfor determining the amount of scattering from the sample.

The light sources used for transmission may be physically mounted in amanner so that their beams will pass through the sample before hittingthe photodiode directly.

The light sources used for fluorescence may be mechanically mounted in amanner so that the detecting photodiode is at an angle to minimizetransmissive signal.

The light sources may be modulated at a fixed frequency and atpre-defined and controlled power levels.

The transmitted, scattered and fluoresced light may be converted to anelectrical signal by use of photosensitive detectors whose signals areamplified then subsequently demodulated to produce a DC signal that ismeasured by an analog to digital converter, wherein demodulation isaccomplished using a balanced demodulator configured as a lock inamplifier.

The concentration of the analyte in the solution is calculated from thecontribution to the detected and demodulated signals from the resultingchromophore or fluorophore from which the contribution of scattering hasbeen subtracted.

In the above description, certain terms may be used such as “up,”“down,” “upper,” “lower,” “horizontal,” “vertical,” “left,” “right,” andthe like. These terms are used, where applicable, to provide someclarity of description when dealing with relative relationships. But,these terms are not intended to imply absolute relationships, positions,and/or orientations. For example, with respect to an object, an “upper”surface can become a “lower” surface simply by turning the object over.Nevertheless, it is still the same object. Further, the terms“including,” “comprising,” “having,” and variations thereof mean“including but not limited to” unless expressly specified otherwise. Anenumerated listing of items does not imply that any or all of the itemsare mutually exclusive and/or mutually inclusive, unless expresslyspecified otherwise. The terms “a,” “an,” and “the” also refer to “oneor more” unless expressly specified otherwise.

Additionally, instances in this specification where one element is“coupled” to another element can include direct and indirect coupling.Direct coupling can be defined as one element coupled to and in somecontact with another element. Indirect coupling can be defined ascoupling between two elements not in direct contact with each other, buthaving one or more additional elements between the coupled elements.Further, as used herein, securing one element to another element caninclude direct securing and indirect securing. Additionally, as usedherein, “adjacent” does not necessarily denote contact. For example, oneelement can be adjacent another element without being in contact withthat element.

As used herein, the phrase “at least one of”, when used with a list ofitems, means different combinations of one or more of the listed itemsmay be used and only one of the items in the list may be needed. Theitem may be a particular object, thing, or category. In other words, “atleast one of” means any combination of items or number of items may beused from the list, but not all of the items in the list may berequired. For example, “at least one of item A, item B, and item C” maymean item A; item A and item B; item B; item A, item B, and item C; oritem B and item C. In some cases, “at least one of item A, item B, anditem C” may mean, for example, without limitation, two of item A, one ofitem B, and ten of item C; four of item B and seven of item C; or someother suitable combination.

Unless otherwise indicated, the terms “first,” “second,” etc. are usedherein merely as labels, and are not intended to impose ordinal,positional, or hierarchical requirements on the items to which theseterms refer. Moreover, reference to, e.g., a “second” item does notrequire or preclude the existence of, e.g., a “first” or lower-numbereditem, and/or, e.g., a “third” or higher-numbered item.

The subject matter of the present disclosure may be embodied in otherspecific forms without departing from its spirit or essentialcharacteristics. The described embodiments are to be considered in allrespects only as illustrative and not restrictive. The scope of thedisclosure is, therefore, indicated by the appended claims rather thanby the foregoing description. All changes which come within the meaningand range of equivalency of the claims are to be embraced within theirscope.

What is claimed is:
 1. A system for detecting and quantifying an analytein a liquid, the system comprising: a vial comprising one or morepre-dosed reagents disposed within the vial, wherein the vial isconfigured to receive and hold a volume of a liquid comprising ananalyte, wherein the one or more pre-dosed reagents are dissolvable inthe volume of the liquid to form a sample liquid solution comprisingchromophores or fluorophores, wherein the analyte and the one or morepre-dosed reagents react to yield the chromophores or fluorophores; anda detection device comprising a chamber configured to retain the vial,the detection device configured to quantify the analyte in the sampleliquid solution.
 2. The system of claim 1, wherein the pre-dosedreagents comprise freeze-dried solid reagents.
 3. The system of claim 1,wherein quantifying the analyte comprises quantifying the chromophoresor fluorophores in the sample liquid solution.
 4. The system of claim 3,wherein the detection device further comprises a plurality of lightsources, each light source configured to emanate light towards thesample liquid solution in the vial.
 5. The system of claim 4, whereinthe detection device further comprises a first photosensitive detectorpositioned in the chamber opposite from at least one of the plurality oflight sources.
 6. The system of claim 5, wherein the detection devicefurther comprises a second photosensitive detector positioned at anangle offset from direct light from plurality of light sources.
 7. Thesystem of claim 6, wherein the plurality of light sources are modulatedat a fixed frequency.
 8. The system of claim 6, wherein the firstphotosensitive detector comprises a photosensor configured to convert alight signal from the plurality of light sources to a voltage signal, anamplifier configured to amplify the voltage signal, and a demodulatorconfigured to convert the voltage signal to a direct current signal. 9.The system of claim 8, wherein the detection device further comprises acontrol system comprising an analog to digital converter to measure thedirect current signal.
 10. The system of claim 6, wherein the firstphotosensitive detector detects transmission of light through the sampleliquid solution.
 11. The system of claim 6, wherein the secondphotosensitive detector detects fluorescence of light from the sampleliquid solution.
 12. The system of claim 3, wherein the detection deviceis further configured to detect light signals that pass through thesample liquid solution and convert the detected light signals intodigital signals to quantify the chromophores or fluorophores in thesample liquid solution.
 13. A detection device for detecting andquantifying an analyte in a liquid, the detection device comprising: achamber configured to receive and retain a vial comprising one or morepre-dosed reagents disposed within the vial, wherein the vial isconfigured to receive and hold a volume of a liquid comprising ananalyte, wherein the one or more pre-dosed reagents are dissolvable inthe volume of the liquid to form a sample liquid solution comprisingchromophores or fluorophores, wherein the analyte and the one or morepre-dosed reagents react to yield the chromophores or fluorophores; aplurality of light sources, each light source configured to emanatelight towards the sample liquid solution in the vial; a firstphotosensitive detector positioned in the chamber opposite from at leastone of the plurality of light sources; and a second photosensitivedetector positioned at an angle offset from direct light from pluralityof light sources.
 14. The detection device of claim 13, wherein thefirst photosensitive detector comprises a photosensor configured toconvert a light signal from the plurality of light sources to a voltagesignal, an amplifier configured to amplify the voltage signal, and ademodulator configured to convert the voltage signal to a direct currentsignal.
 15. A method for detecting and quantifying an analyte in aliquid, the method comprising: forming a sample liquid solution byinserting a volume of a liquid comprising an analyte into a vial withone or more pre-dosed reagents dissolvable in the volume of the liquidto form a sample liquid solution comprising chromophores orfluorophores, wherein the analyte and the one or more pre-dosed reagentsreact to yield the chromophores or fluorophores; and quantifying theanalyte in the sample liquid solution by quantifying the chromophores orfluorophores in the sample liquid solution.
 16. The method of claim 15,wherein quantifying the chromophores or fluorophores in the sampleliquid solution comprises detecting light transmission through thesample liquid solution using a first photosensitive detector positionedopposite a plurality of light sources and detecting light fluorescencefrom the sample liquid solution using a second photosensitive detectorpositioned offset from direct light emanation from the plurality oflight sources.
 17. The method of claim 16, further comprising modulatingthe light sources at a fixed frequency.
 18. The method of claim 16,further comprising converting the detected light transmission to anelectrical signal.
 19. The method of claim 18, wherein converting thedetected light transmission to an electrical signal comprises convertingthe detected light transmission to a voltage signal, amplifying thevoltage signal, and converting the amplified voltage signal to a directcurrent signal.
 20. The method of claim 15, wherein quantifying theanalyte in the sample liquid solution comprises detecting absorbance inthe sample liquid solution.